[ Ссылка ]
How to tell if a coin is cleaned. Cleaned coins come in different appearances and it is important to know what that looks like.

Refraction: the fact or phenomenon of light, radio waves, etc., being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density.

Translucency: is a superset of transparency: it allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction.

свернуть